Some 62 million hectares of pasture (about 153 million acres, an area three times the size of the UK) has been abandoned around the world over the past 15 years — the first significant decline in recorded history.

Pastureland shrunk in 65 countries, but at the same time production from grazing animals actually increased by 35 percent.

Independent Joseph Poore argues that we could seize the opportunity afforded by the decline in pastureland to restore natural habitat through reforestation and reestablishment of natural grasslands.

New evidence that global pasture extent is declining presents an important conservation opportunity, according to a researcher.

Some 62 million hectares of pasture (about 153 million acres, an area three times the size of the UK) has been abandoned around the world over the past 15 years — the first significant decline in recorded history, according to a letter published in the journal Science by independent researcher Joseph Poore.

Pastureland shrunk in 65 countries, Poore found, but at the same time production from grazing animals actually increased by 35 percent. Just 15 of those 65 countries saw an increase in total agricultural land, which saw an overall decline of 109 million hectares (nearly 270 million acres).

“This implies that pasture land is not being used for different agricultural purposes, and instead suggests that an area approximately the size of South Africa may have recently been abandoned,” Poore writes in the Science letter.

In other words, Poore told Mongabay, we are producing more from less. And the trend appears to be permanent, he added, as there have been annual declines almost every year since 1998.

“A major reason for this trend is that grazing practices are becoming more intense, occupying less land,” Poore said. “Farmers are therefore abandoning the lowest productivity land around the world.”

There are likely a number of factors at play that are making grazing more intensive and less mobile, Poore writes in the letter, including changing economic and environmental conditions. He uses Australia as an example: the country is responsible for a large share of the decline in pastureland, likely due to declining stocks thanks to 25 years of low wool prices, as well as desertification and woody encroachment, which have reduced productive pasture area.

Meanwhile, in Iran, Mongolia, Turkmenistan, and Uzbekistan, all countries that also saw substantial declines, land and livestock privatization, urbanization, and changing management practices have concentrated production into smaller areas.

Poore argues that we could seize the opportunity afforded by the decline in pastureland to restore natural habitat through reforestation and reestablishment of natural grasslands. “The land could be restored to its original condition as wild grasslands or forest, supporting the return of biodiversity,” he said.

Whatever conservationists choose to make of this opportunity, Poore wrote in the Science letter, they need to move quickly, because there are already others eyeing those same abandoned pastures.

But before deciding what to ultimately do with the land, we will have to answer a number of questions, Poore wrote:

“Will the land become wild again naturally, meaning no action is required? Is it most productive to build relationships with landowners to facilitate conservation goals? Given that land values are likely low, is this a chance for opportunistic and targeted land acquisitions that could serve as foundations for new protected areas?”

There is some action already, Poore said, though it has been limited, especially given the amount of land in question. One major exception, he points out, is the charity Greening Australia, which has been acquiring abandoned land to create a wildlife corridor called the Gondwana Link.

There are some who claim we should use the pastureland for biofuels, but a 2008 study found that even if we we were to cultivate a massive 750 million hectares (nearly 1.9 billion acres) of abandoned land, it would only meet 5 percent of the world’s energy demand.

There’s also the animal welfare and climate issues to contend with. Farming intensification can have detrimental effects on animals, so we must be certain we’re not simply substituting the maltreatment of the land for mistreating livestock.

And of course, even if you’re producing more animal products from less land, you’re still likely producing more greenhouse gas emissions, at precisely the time that the world is trying to rein in those emissions in order to combat global warming.

“To be clear, pasture is still expanding fast in highly sensitive ecosystems, particularly in South America,” Poore said.

“Ruminants are also a major source of greenhouse gas emissions, among other environmental problems. The only truly environmentally friendly route is to avoid their consumption altogether. [But] before this diet change happens, this is a conservation opportunity we must act on.”